It's been encrypted pretty naively, pretty simplistically, but it's actually an English sentence that's been somehow scrambled; but scrambled in a reversible way.

它被天真地，相当简单地加密了，但是它实际上是一个被加密的英语句子,但是加密方式是可逆的。

哈佛公开课 - 计算机科学课程节选